WO 2008/038245 and WO 2010/052142 disclose a high-pressure discharge lamp, in which a metal halide fill with Gd for the light color daylight is used. The high-pressure discharge lamp contains, as metal halide, Gd together with rare-earth iodides. In this case, the discharge vessel consists of ceramic, wherein the wall loading is in the range of from 20 to 40 W/cm2. The fill quantities are selected to be relatively high in order to achieve a color temperature of typically from 5000 to 6500 K corresponding to the light color daylight.
A higher light color such as skywhite has has until now (see WO 2005/100508) only been achieved by fluorescent lamps.